* keep track of delta interval versions and skip deltas
that are not consequtive, i.e. when some delta message was lost
* send the delta versions in the full state gossip to sync up the
expected versions after dropped deltas
* implementation of deltas for ORSet
* refactoring of the delta types to allow for different type for the
delta and the full state
* extensive tests
* mima filter
* performance optimizations
* simple pruning of deltas
* Java API
* update documentation
* KeyId type alias
* Use InternalApi annotation
* delta GCounter and PNCounter
* first stab at delta propagation protocol
* send delta in the direct write
* possibility to turn off delta propagation
* tests
* protobuf serializer for DeltaPropagation
* documentation
* fix merge issues of DataEnvelope and its pruning
* simplify by removing the tombstones, which didn't work in all cases anyway
* keep the PruningPerformed markers in the DataEnvelope until configured
TTL has elapsed (wall clock)
* simplify PruningState structure
* also store the pruning markers in durable data
* collect removed nodes from the data, listing on MemberRemoved is not enough
* possibility to disable pruning altogether
* documented caveat for durable data
The WriteAggregator and ReadAggregator typically send
the same message to several replicas and by caching the serialized bytes
we avoid doing the same thing for each message
and add a test for WriteAggregator
Previously know as [patriknw/akka-data-replication](https://github.com/patriknw/akka-data-replication),
which was originally inspired by [jboner/akka-crdt](https://github.com/jboner/akka-crdt).
The functionality is very similar to akka-data-replication 0.11.
Here is a list of the most important changes:
* The package name changed to `akka.cluster.ddata`
* The extension was renamed to `DistributedData`
* The keys changed from strings to classes with unique identifiers and type information of the data values,
e.g. `ORSetKey[Int]("set2")`
* The optional read consistency parameter was removed from the `Update` message. If you need to read from
other replicas before performing the update you have to first send a `Get` message and then continue with
the ``Update`` when the ``GetSuccess`` is received.
* `BigInt` is used in `GCounter` and `PNCounter` instead of `Long`
* Improvements of java api
* Better documentation
